/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.db.metadata.tagSchemaRegion.config;

import org.apache.iotdb.commons.conf.IoTDBConstant;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.*;
import java.util.Properties;

/**
 * manager tag schema config
 */
public class TagSchemaDescriptor {
    private static final Logger logger = LoggerFactory.getLogger(TagSchemaDescriptor.class);

    private static final String TAG_SCHEMA_CONFIG_FILE_NAME = "schema-tag.properties";

    private final TagSchemaConfig conf = new TagSchemaConfig();

    private TagSchemaDescriptor() {
        loadProperties();
    }

    public static TagSchemaDescriptor getInstance() {
        return TagSchemaDescriptorHolder.INSTANCE;
    }

    private void loadProperties() {
        String iotDBHomePath = System.getProperty(IoTDBConstant.IOTDB_HOME, null);
        if (iotDBHomePath == null) {
            logger.warn(
                    "Cannot find IOTDB_HOME environment variable when loading "
                            + "config file {}, use default configuration",
                    TAG_SCHEMA_CONFIG_FILE_NAME);
            return;
        }
        String tagSchemaConfigPath =
                iotDBHomePath
                        + File.separatorChar
                        + "conf"
                        + File.separatorChar
                        + TAG_SCHEMA_CONFIG_FILE_NAME;
        try (InputStream in = new BufferedInputStream(new FileInputStream(tagSchemaConfigPath))) {
            Properties properties = new Properties();
            properties.load(in);
            conf.setWalBufferSize(
                    Integer.parseInt(
                            properties.getProperty("wal_buffer_size", String.valueOf(conf.getWalBufferSize()))));
            conf.setNumOfDeviceIdsInMemTable(
                    Integer.parseInt(
                            properties.getProperty(
                                    "num_of_deviceIds_in_memTable",
                                    String.valueOf(conf.getNumOfDeviceIdsInMemTable()))));
        } catch (FileNotFoundException e) {
            logger.warn("Fail to find tag schema region config file {}", tagSchemaConfigPath);
        } catch (IOException e) {
            logger.warn("Cannot load tag schema region config file, use default configuration");
        }
    }

    public TagSchemaConfig getTagSchemaConfig() {
        return conf;
    }

    private static class TagSchemaDescriptorHolder {

        private static final TagSchemaDescriptor INSTANCE = new TagSchemaDescriptor();

        private TagSchemaDescriptorHolder() {
        }
    }
}
